Classroom Struggle

I think I need to be kinder- and stricter- in my classroom. I am noticing myself beginning to get tired- that first streak of it- and loosing patience with the kids. There are times when it feels like I've tried everything that I'm supposed to do- calling parents, giving write-ups, enforcing my consequences, every time (though I'm sure I'm still being too lenient). But I feel like I'm loosing them anyway. (Granted, not every class, but yesterday was not good.) Usually I would be able to step back, think of how my attitude is influencing my classroom, and adjust. As usual, I think not getting enough sleep made a big difference yesterday, but it should be automatic. I should know how I need to react in every situation. I wouldn't want to be spoken to the way I spoke to my kids yesterdays (well, one class). I don't think it was productive, and it certainly did not feel like leadership in the classroom. I should have given them a pop quiz, switched to silent work for the remainder of the period, and called it a day. Hindsight. Some of my kids seem like they like my class, but some of them- especially in the tougher classes- still complain about. It seems to come very naturally to many other teachers, and I can't help but wonder if I'm missing some key ingredient.